Footnotes

Older Autoconf versions used
‘configure.in’. Autoconf 2.50 and greater promotes
‘configure.ac’ over ‘configure.in’. The rest of this
documentation will refer to ‘configure.ac’, but Automake also
supports ‘configure.in’ for backward compatibility.

Please note that automake recognizes
‘-d’ in AM_YFLAGS only if it is not clustered with other
options; for example, it won’t be recognized if AM_YFLAGS is
‘-dt’, but it will be if AM_YFLAGS is ‘-d -t’ or
‘-d -t’

For example,
the cfortran package
addresses all of these inter-language issues, and runs under nearly all
Fortran 77, C and C++ compilers on nearly all platforms. However,
cfortran is not yet Free Software, but it will be in the next
major release.